1. Field of the Invention
The present invention relates to an air circulation system of a liquid electrophotographic printer.
2. Description of the Related Art
A liquid electrophotographic printer such as a color laser printer, as shown in FIG. 1, includes a photoreceptor belt 10 circulating in one direction, a developing unit 20 having a developing roller 21 and a squeegee roller 23 for developing an electrostatic latent image formed on the photoreceptor belt 10, a drying unit 30 for drying the developed image, and a transferring unit 40 for printing the developed image on printer paper. These units are installed inside an engine shell 50 which is sealed to prevent intrusion of foreign material from the outside.
During a printing process, developer which is a mixture of toner and liquid carrier is provided to the photoreceptor belt 10 by means of the developing roller 21 in the developing unit 20. Subsequently, excess developer not used in the above developing process is removed by the squeegee roller 23. In doing so, an air injector 25 injects air so that the excess developer is prevented from flowing in a reverse direction, thus dropping downward.
Here, the air injected from the air injector 25 is supplied via a supply path 63 by a supply pump 61 installed outside the engine shell 50. The same amount of air supplied into the engine shell 50 by the air injector 25 should be exhausted from the engine shell 50 to the outside in order to maintain constant pressure in the engine shell 50. For this purpose, an exhaust pump 71 for exhausting the air from the engine shell 50 is installed. The air taken via an exhaust opening 51 of the engine shell 50 by a driving force of the exhaust pump 71 is exhausted through an exhaust path 73 and a filter 75.
However, in a liquid electrophotographic printer having the above structure, since a pump for injecting air and a pump for exhausting air are used, a large amount of space for the pumps is needed and accordingly a large amount of noise and vibration are generated.